Autonomous travel-type cleaners provided with a body on which various components are mounted, a driving unit moving the body, a main brush, and a suction unit are disclosed in the related art (refer to, for example, PTL 1 and PTL 2). The main brush is placed at a suction port formed in the body and collects rubbish present on a cleaning surface. The suction unit suctions the rubbish from the suction port in the body.
The autonomous travel-type cleaners disclosed in a number of patent documents such as PTL 1 and PTL 2 have substantially circular bodies. These shapes of the bodies give the autonomous travel-type cleaners a high level of turning performance.
The autonomous travel-type cleaners according to the related art that have the circular bodies cause a relatively wide gap to be formed between the suction port in the body and a tip part of a corner even if the autonomous travel-type cleaner approaches the corner in an object region to the maximum extent possible. Accordingly, in some cases, the rubbish that is present at the corner in the object region cannot be sufficiently suctioned by the suction unit.
Autonomous travel-type cleaners that further include one or more side brushes placed on a bottom surface of the body are disclosed so that the above-described problem can be addressed (refer to, for example, PTL 3 to PTL 6). The side brush is provided with a bristle bundle sticking out from the outline of the body. The bristle bundle collects the rubbish present outside the outline of the body in the suction port of the body. Accordingly, the autonomous travel-type cleaners disclosed in PTL 3 to PTL 6 can suction more of the rubbish present at the corner in the object region.
The ability of the autonomous travel-type cleaners disclosed in PTL 3 to PTL 6 to suction the rubbish present at the corner in the object region (hereinafter, simply referred to as a “corner cleaning ability” in some cases) is regarded as being determined mainly by the side brush. The length of the bristle bundle, in the meantime, is set under various constraints. Accordingly, the corner cleaning ability obtained based on the side brush is also affected by the constraint. In other words, the autonomous travel-type cleaners disclosed in PTL 3 to PTL 6 have room for improvement in terms of the corner cleaning ability.
An example of the autonomous travel-type cleaner with a further improved corner cleaning ability is also disclosed (refer to, for example, PTL 7).
The autonomous travel-type cleaner disclosed in PTL 7 is provided with a substantially D-shaped body, a suction port formed in a bottom surface of the body, and a pair of side brushes attached to corners of the bottom surface of the body.
At the position of the corner in the object region, this autonomous travel-type cleaner allows the axis of the side brush and the suction port of the body to approach a vertex of the corner to a greater extent than the autonomous travel-type cleaners disclosed in, for example, PTL 3 to PTL 6.
Accordingly, more of the rubbish becomes likely to be suctioned by the body. In a case where the autonomous travel-type cleaner disclosed in PTL 7 is positioned at the corner in the object region, however, a front surface and one side surface of the body come into contact with a wall that forms the corner or approach the wall to the point of being comparable to the contact. Accordingly, this autonomous travel-type cleaner cannot rotate in that place in some cases.
In other words, a relatively significant constraint is imposed on the operation trajectory of the autonomous travel-type cleaner disclosed in PTL 7 when the autonomous travel-type cleaner moves to another place from a cleaned corner in the object region after the cleaning of the corner is completed.